I returned to university to get a 2nd degree in Computer Science after realizing how poor my job options were with my philosophy degree. The benefit of a 2nd degree, at least in the Canadian system (I'm not sure how it works in Ireland), is that you don't need to fulfil all of the elective credits, so you can complete a second degree in 2 years.

Having been through the degree, I am glad I did it, but I'm not sure it's the best and quickest path to a career as a developer. There was a lot of time spent on learning theory and history of the discipline, that may have been better spent on doing. Programming is definitely best learned by doing.

It is a tough decision to make. Many employers still hold the degree up high as a hiring requirement. You already have one of these.

My advice would be to explore your options. Try out some self-learning. There are many great books and online tutorials out there to learn from. Play around with the field a bit before committing to another degree.